PROJECT SUMMARY The long-term objective of the Clinical Trial Core will be to facilitate the Scientific Objectives, Aims and Goals of the Center by supporting/undertaking two prospective clinical trials and ensuring that these activities are performed in compliance with ICH/GCP Guidelines, Health Canada and local IRB regulatory requirements. In Project 1 a randomized, double-blind, placebo-controlled trial of peptide immunotherapy will be performed in 48 subjects with cat-allergic rhinitis in order to obtain peripheral blood samples from which allergen-specific T cells will be enrich and characterized to determine their frequency and functional phenotype before, immediately after, and 1 year after, peptide immunotherapy. In Project 2 a total of 48 cat-allergic asthmatic subjects will be subjected to segmental lung allergen challenge (with saline control segment). Peripheral blood and bone marrow will be taken before and after the lung challenge and bronchoalveolar lavage will be performed on saline- and allergen-challenged lobes 24 hours post-challenge. Allergen-specific T cells will be enriched and characterized from each compartment. The Specific Aims of Clinical Trial Core B will be; Aim 1: to provide clinical oversight and resources (personnel, equipment and knowledge). Aim 2: to ensure recruitment of adequate numbers of well characterized study subjects. Aim 3: to ensure the safety of all study participants by monitoring compliance with ICH/GCP and providing expert medical surveillance. Aim 4: to provide clinical expertise to facilitate the collection of standardized, high quality clinical samples required to support the scientific aims, and fulfill the goals, of the Center. Aim 5: to liaise with Administrative Core A to complete and manage all of the required regulatory documents (including local Research Ethics Board/Institutional Review Board; REB/IRB) and to facilitate communication of clinical issues between the Center, the REB/IRB, the Scientific Advisory Panel (SAP) and NIH Program staff.